Like an insidious virus, a string of bomb threats has plagued schools in the region over the last couple of weeks, causing school administrators, parents and students to scratch their heads about what might have sparked this epidemic.

The bombing at the Boston Marathon last month may have set off a wave of wannabe copycats. But experts suggest that there are a variety of explanations for the threats. Just like a virus, they said, bad behavior can spread among teenagers like wildfire -- particularly when it yields a benefit, such as getting out of school early.

Over the past couple of weeks, there have been eight bombs threats in the Bridgeport schools alone, with another at Emmett O'Brien Technical High School in Ansonia at the beginning of last week. At Bridgeport's Bassick High School, the site of several of the threats, some students have even begun to anticipate a daily evacuation from school. "It seems to have become a trend," said Demetri Smith, a Bassick senior. "It's got to the point when, if I have something to give to the teachers or get done, I do it before fourth period because that's when it usually happens."

The incidents in Bridgeport and Ansonia are just some examples of recent bomb threats, said State Police Lt. J. Paul Vance. He said there have been similar threats throughout the state.

A quick Web search showed that at least half a dozen other threats have been reported throughout the state since January, including one at Weston High School in February and Shelton High in March. In April, Greenwich High School was locked down after reports, mistakenly it turned out, that a student had a gun.

State police take all threats seriously, and respond to each of them with officers and bomb-sniffing dogs, Vance said.

"That sends a message right off the bat that this is a criminal investigation," he said.

A 17-year-old boy was charged in connection with the O'Brien threat and another has been charged with some of the Bassick threats.

Vance couldn't say definitively whether there have been more bomb threats this year than in the past but "I do think they're more publicized more and we're more aware of them."

Connecticut isn't the only state struggling with threats. States as diverse as Illinois, Texas and California are all home to schools where there have been recent bomb threats. For instance, at Oakwood School in Lemont, Ill., someone reportedly scrawled a threat on a wall last weekend. Many of the Connecticut threats also were written on walls.

Bridgeport Superintendent of Schools Paul Vallas said he has led school districts since 1995 and finds that usually when something happens on the national level -- like the Boston bombing -- things will happen in the local districts. "These things come in clusters," Vallas said. When he was in Chicago, a city with 86 high schools, he recalls spending the better part of a month dealing with bomb scares.

But other experts said the threats were likely perpetrated by cabin-fever-plagued kids impatient for summer vacation. "Quite often, near the end of the school year, kids can carry out bomb scares to get out of school," said Kenneth Gray, a retired FBI agent and a lecturer in criminal justice at the University of New Haven.

Gray quickly dismissed the notion that the scares were inspired by the Boston Marathon bombing, even though they came so quickly in that incident's wake. He said high-profile incidents like Boston can bring out copycats, but they tend to copy the exact instigating incident.

He said copycat behavior like this is also called social imitation and happens a lot in the animal kingdom, where whales and other creatures learn skills by watching others. Unfortunately, among teenagers, Kazdin said, it frequently happens with negative behaviors, such as suicide or threats. Like Gray, he said media attention can hasten the spread of troubling behavior.

"When there's a suicide and it gets publicity, you'll see a little blip of other suicides," he said. It's the same with the bomb threats, Kazdin said. "Contagion is a real thing."

The publicity isn't necessarily through mainstream media. In this age of social media, word of these incidents can spread like wildfire through sites like Facebook and Twitter, Gray said.

"When one kid posts that they got out of school because of a bomb threat, everyone sees it," he said.

So how do you stop these outbreaks? One solution is to remove incentives. In the case of bomb threats, that means not letting students go home once it's been determined there's no danger. Bridgeport has already changed its reaction. When Bassick was evacuated the first time last week, a number of students just went home. Since then the district has treated the situation like a fire drill and gets students back inside as soon as possible. The schools also have adopted what Bridgeport superintendent Vallas called preemptive measures, such as security sweeps in the morning before kids enter the building.

John Perotta, head of security for Stamford public schools, said the protocol for his district is to investigate threats, but to hold off on clearing out the school.

"We look at all of them, but we don't automatically evacuate," he said. "Only if it is a credible threat."

A few years back, Perotta said, a couple of different schools in that district were hit with a spate of phony bomb threats within a short span of time. He said they had a strong sense of who was behind the threats but police could not get enough evidence to make an arrest.

"But they did get the message across to stop calling and they stopped calling," said Perotta.